The invention relates to the technical field of false ceilings and taut false walls.
In the prior art, there already exist a large number of embodiments of these false ceilings.
By way of example, reference can be made to the patent applications in France published under the following numbers: 2 767 851, 2 751 682, 2 734 296, 2 712 006, 2 707 708, 2 703 711, 2 699 211, 2 699 209, 2 695 670, 2 691 193, 2 688 849, 2 685 036, 2 645 135, 2 630 476, 2 627 207, 2 624 167, 2 623 540, 2 619 531, 2 597 906, 2 611 779, 2 592 416, 2 587 447, 2 561 690, 2 587 392, 2 552 473, 2 537 112, 2 531 012, 2 524 922, 2 475 093, 2 486 127, 2 523 622, 2 310 450, 2 270 407, 2 202 997, 2 175 854, 2 145 147, 2 106 407, 2 078 579, 2 002 261, 1 475 446, 1 303 930, 1 287 077.
For examples, reference can also be made to the following documents: U.S. Pat. No. 5,058,340; U.S. Pat. No. 4,083,157; U.S. Pat. No. 4,083,157; EP-A-643 180, EP-A-652 339, EP-A-588 748, EP-A-504 530, EP-A-338 925, EP-A-281 468, EP-A-215 715, EP-A-089 905, EP-A-043 466, WO-A-94/12741, WO-A-92/18722.
It is also possible to consult by way of example the following patent applications in France of the Applicant: 736 615, 2 756 600, 2 727 711, 2 712 325, 2 699 613, 2 695 670, 2 692 302, 2 658 849.
Known materials of the prior art for embodying taut false ceilings or taut false walls are most often polymer materials provided with a large number of qualities, such as in particular fire resistance, impervious to air and thus be impervious to dust or humidity, and facility of maintenance.
False ceilings obtained with the aid of these materials can incorporate insulating materials, spotlights or various lighting, as well as ventilation or aeration openings or sprinklers.
As they can be dismantled, intervention can be effected in the plenum.
Polymer materials for known taut ceilings in the prior art, which may be translucent or opaque, possibly fully tinted, mat, lacquered, marbled, suede or velvet-finished, can therefore be used in an industrial environment, a hospital environment, for collective equipment, laboratories or dwellings.
The lacquered finish makes it possible to have a mirror effect often implemented in commercial centres, a relatively mat finish approaching a plaster aspect being more usual in traditional decors.
In a former technique, the fabrics or top sheets at the ceiling or at a wall being definitively fixed by means of points or staples.
Conventional taut false ceilings currently include                firstly, a horizontal frame secured to the upper portion of the walls of a room, this frame being an external heald formed by butt-jointed sectional bars;        secondly, a lap stretched horizontally inside this frame.        
This disposition enables elements at the taut ceiling to be dismantled.
Supporting of the lap with respect to the heald frame is obtained by various means, several examples being given below.
According to a first type of embodiment, the heald includes a U-shaped throat limited by two walls, one of the two walls having a lip orientated towards the bottom of the throat, hooks placed on the circumference of the lap being firmly anchored on this lip.
For this first type of embodiment, reference can be made to the document FR-A-1 303 930.
According to a second type of embodiment, the heald includes a U-shaped throat limited by two walls, one of the two walls including a shoulder having one portion situated towards the bottom of the throat forming a stop.
For this second type of embodiment, reference can be made to the documents FR-A-1 475 446 and FR-A-2 002 261.
According to a third type of embodiment, the heald is a flat profile, the lap being squeezed between this profile and the wall on which it is fixed.
For this third type of embodiment, reference can be made to for example the document FR-A-2 734 296.
According to a fourth type of embodiment, the heald is provided with means forming tension and fitting pliers.
For this fourth type of embodiment, reference can be made for example to the documents FR-A-2 699 211 and FR-A-2 537 112.
According to a fifth type of embodiment, the heald is provided with a throat in which hook-shaped elements integral with the lap can be gripped in the way of a harpoon.
For this fifth type of embodiment, reference can be made for example to the documents FR-A-2 630 476 and EP-A-388 925.
In frames of taut ceilings of the prior art, regardless of the means for retaining tension of the lap on the heald frame. (stop, cramp irons, forked ties, clamping, catching . . . ), the healds are normally made of an extruded polymer material.
For the most part, taut ceilings are moreover mounted with their lap fully taut.
In certain particular embodiments with the lap being taut on a horizontal heald frame secured to the walls of a room, deformations of the taut lap are embodied, as described in the documents FR-A-1 515 260 and EP-A-281 468.
Thus, the document EP-A-281 468 describes a false ceiling comprising a taut lap hooked along its edges to a horizontal support frame constituted by butt-jointed profile bars fixed to the walls of a room. Above the lap, means are placed exerting on the lap on at least one point an adjustable force provoking its deformation. These means include a cable moving through a pulley fixed to the ceiling of a room, said cable supporting a heavy weight on the lap.